In the last few years, Downey has attracted massive audiences to his films, including the "Sherlock Holmes" movies, and this week Disney announced Downey will appear in two more "Avengers" movies, meaning his star power should stay strong.

HTC declined to confirm the report.

"But as we've said over the past several months, HTC is working to change its approach in how and where it markets its products to compete in a more effective manner," HTC said in a statement.

But even with the addition of Downey, taking on Apple and Samsung will be a Herculean task.

Samsung, in particular, spends billions of dollars on marketing each year, and at times, the South Korean tech giant enlists multiple movie stars in its commercials to promote its devices.

The company's Super Bowl commercial this year, for example, featured actors Paul Rudd and Seth Rogan as well as NBA MVP LeBron James. And this month, Samsung teamed up with hip-hop superstar Jay-Z for a marketing blitz that will give the rapper's next CD away for free to 1 million Samsung device owners.